1. Field of the Technology
The present invention relates to network transmission techniques using Multi-Protocol Label Switching (MPLS), more particularly to a method for handling a fault between an Egress Label Switching Router (Egress LSR) and a data device connected with it.
2. Background of the Invention
Currently, the MPLS has become a key technique for multi-service bearers in an Internet Protocol (IP) network. Accordingly, fault detection and protection switching technique for the MPLS becomes an important factor that impacts the normal operation of the IP network. Corresponding standards for implementing the fault detection and the protection switching technique for MPLS networks defined by International Telecommunication Union-Telecommunication sector (ITU-T) are shown in Table 1.
Protocol NumbersTitlesY.1710Requirements for Operation And Maintenance (OAM)functionality for MPLS networksY.1711OAM mechanism for MPLS networksY.1720Protection switching for MPLS networks
Referring to Table 1, the standard Y.1711 defines an end-to-end fault detection mechanism for the MPLS networks, namely the Operation and Maintenance (OAM) fault detection mechanism. The standard Y.1720 defines an end-to-end protection switching mechanism for the MPLS networks. The end-to-end mentioned here refers to from an Ingress Label Switching Router (Ingress LSR) to an Egress LSR that both adopt the MPLS technique.
According to the standards Y.1711 and Y.1720, if a Work Label Switching Path (Work LSP) between an Ingress LSR and an Egress LSR is failed, the Egress LSR sends a Backward Defect Indication (BDI) packet to the Ingress LSR. After receiving the BDI packet, the Ingress LSR operates the corresponding protection switching process.